Strong inclination pacing of climate in Late Triassic low latitudes revealed by the Earth-Saturn tilt cycle

Gravitational interactions among masses in the solar system are recorded in Earth’s paleoclimate history because variations in the geometry of Earth’s orbit and axial orientation modulate insolation. However, astronomical models are unreliable before ~50 Ma due to the chaotic nature of the solar system and therefore must be constrained using geological observations. Here, we use environmental proxies from paleo-tropical Late Triassic lake deposits of the Newark Rift Basin to identify and tune to previously undescribed strong variations in orbital inclination. Tuning to the 173 kyr Earth-Saturn inclination cycle, theoretically stable due to the high mass of Saturn, reveals both other predicted inclination cycles and previously reported eccentricity cycles. Slight, complementary offsets in the eccentricity and inclination cycles shown by the Earth-Saturn (s3-s6) and Venus-Jupiter (g2-g5) tunings may be due to chaotic variations of the secular fundamental frequencies in Earth’s nodal and Venus’s perihelion orbital precessions. The strength of the inclination cycles suggests that the Earth system modulates orbital pacing of climate and provides a mechanism to further constrain astronomical solutions for solar system dynamics beyond the ~50 Ma limit of predictabilit

Synchrony between the Central Atlantic magmatic province and the Triassic-Jurassic mass-extinction event?

We present new data and a synthesis of cyclostratigraphic, lithostratigraphic, biostratigraphic, and published magnetostratigraphic and basalt geochemical data from eastern North America and Morocco in an attempt to clarify the temporal relationship between the Triassic–Jurassic mass extinction (∼ 202 Ma) and Earth's largest sequence of continental flood basalts, the Central Atlantic magmatic province (CAMP). Newly discovered zones of reverse polarity within CAMP flow sequences of Morocco have been hypothesized by Marzoli et al. [Marzoli, A., Bertrand, H., Knight, K.B., Cirilli, S., Buratti, N., Vérati, C., Nomade, S., Renne, P.R., Youbi, N., Martini, R., Allenbach, K., Neuwerth, R., Rapaille, C., Zaninetti, L., Bellieni, G., 2004. Synchrony of the Central Atlantic magmatic province and the Triassic–Jurassic boundary climatic and biotic crisis. Geology 32, 973–976.] and Knight et al. [Knight, K.B., Nomade, S., Renne, P.R., Marzoli, A., Betrand, H., Youbi, N., 2004. The Central Atlantic Magmatic Province at the Triassic–Jurassic boundary: paleomagnetic and 40Ar/30Ar evidence from Morocco for brief, episodic volcanism. Earth and Planetary Science Letters 228, 143–160.] as correlates of a very short, uppermost Triassic age reverse chron in the Newark basin, thus suggesting that much of the Moroccan CAMP was synchronous with or predates the Triassic–Jurassic boundary. Here, however, we explain these apparent reverse polarity zones as possible correlatives of poorly sampled lower Jurassic basalt flow sequences and overlying strata in eastern North America and lower Jurassic reverse polarity sequences recognized by others in the Paris basin. A revised Milankovitch cyclostratigraphy based on new core and field data constrains the duration of eastern North America basaltic flows to ∼ 610 ky after the Triassic–Jurassic palynological turnover event. Palynological data indicates correlation of the initial carbon isotopic excursion of Hesselbo et al. [Hesselbo, S.P., Robinson, S.A., Surlyk, F., Piasecki, S., 2002. Terrestrial and marine extinction at the Triassic–Jurassic boundary synchronized with major carbon-cycle perturbation: a link to initiation of massive volcanism. Geology 30, 251–254.] at St. Audrie's Bay to the palynological turnover event and vertebrate extinction level in eastern North America, suggesting a revised magnetostratigraphic correlation and robust carbon isotopic tests of the Marzoli–Knight hypothesis. We conclude that as yet there are no compelling data showing that any of the CAMP predated or was synchronous with the Triassic–Jurassic extinction event

Synchrony between the Central Atlantic magmatic province and the Triassic-Jurassic mass-extinction event? Reply to Marzoli et al.

We are very pleased with the attention, long overdue, that the Triassic–Jurassic boundary and associated events, such as the CAMP, are receiving. This can only lead to greater specificity of hypotheses and greater understanding in the long run, and it is worth emphasizing some broad areas of agreement. Marzoli et al. (2008-this volume) points out the closeness in time of CAMP and Tr–J extinctions, and on this we all agree. We also agree that the systematic differences among different isotopic systems used for dating is a challenge to determining the relative timing of events dated with different techniques. This problem, however, seem to be fading as high-precision single-crystal U–Pb dates (206Pb/238U) are available from a variety of tuffs interbedded with marine strata as well as the North Mountain Basalt of Nova Scotia, which lies above the palynological Triassic–Jurassic extinction event in Nova Scotia. Schoene et al. (2006) obtained an age of 201.27 ± 0.03 Ma from this basalt, which is very close to an age of 201.5 Ma for a tuff 1 m above the last local occurrence of the topmost Triassic guide-fossil, the ammonite Choristoceras in a marine section in Peru (Schaltegger et al., 2007), presumably very close to the Triassic–Jurassic extinction event. Schaltegger et al. (2007) also obtained an age of 199.5 Ma for the Hettangian–Sinemurian boundary from the latter section. Consistent with these ages, Pálfy and Mundil (2006) obtained ages of 200.6 ± 0.3 Ma for an ash layer in ammonite-bearing Middle Hettangian marine sediments in, Alaska, and 198.0 ± 0.6 Ma for a tuff layer in Early Sinemurian sediments in Hungary. These dates are not compatible with the multi-crystal age for the Triassic–Jurassic boundary of 199.6 ± 0.3 Ma of Pálfy and Mundil (2006), a fact recognized by Pálfy and Mundil (2006). Thus, we are in complete agreement that the Triassic–Jurassic extinction event is extremely close in time to the onset of the CAMP. The question is, "are any of the known flows of the CAMP actually at or before this extinction event?". That is the key issue dealt with by Whiteside et al. (2007), and it is a possibility that we recognize as completely plausible, but not yet demonstrated. It is in that spirit of general agreement that we reply to Marzoli et al.'s, comment. We note, however, that their comment touches on far too many points to adequately address in this reply, and we chose to focus our response on their most substantive issues, recalling that our paper was focusing on the testable aspects of their overall hypothesis. We deal with their criticisms in the order they present them

Digital Feast: Narrative review

First paragraph: Overweight and obesity is the second leading cause of cancer in the UK after smoking. Overweight and obesity causes 13 different types of cancer and over 22,000 cancer cases each year in the UK. It is estimated that each year, obesity costs the NHS in England £6.1bn and the wider UK economy £27bn

Climatically driven biogeographic provinces of Late Triassic tropical Pangea

Although continents were coalesced into the single landmass Pangea, Late Triassic terrestrial tetrapod assemblages are surprisingly provincial. In eastern North America, we show that assemblages dominated by traversodont cynodonts are restricted to a humid 6° equatorial swath that persisted for over 20 million years characterized by "semiprecessional" (approximately 10,000-y) climatic fluctuations reflected in stable carbon isotopes and sedimentary facies in lacustrine strata. More arid regions from 5-20°N preserve procolophonid-dominated faunal assemblages associated with a much stronger expression of approximately 20,000-y climatic cycles. In the absence of geographic barriers, we hypothesize that these variations in the climatic expression of astronomical forcing produced latitudinal climatic zones that sorted terrestrial vertebrate taxa, perhaps by excretory physiology, into distinct biogeographic provinces tracking latitude, not geographic position, as the proto-North American plate translated northward. Although the early Mesozoic is usually assumed to be characterized by globally distributed land animal communities due to of a lack of geographic barriers, strong provinciality was actually the norm, and nearly global communities were present only after times of massive ecological disruptions

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Developing community-based scientific priorities and new drilling proposals in the southern Indian and southwestern Pacific oceans

An International Ocean Discovery Program (IODP) workshop was held at Sydney University, Australia, from 13 to 16 June 2017 and was attended by 97 scientists from 12 countries. The aim of the workshop was to investigate future drilling opportunities in the eastern Indian Ocean, southwestern Pacific Ocean, and the Indian and Pacific sectors of the Southern Ocean. The overlying regional sedimentary strata are underexplored relative to their Northern Hemisphere counterparts, and thus the role of the Southern Hemisphere in past global environmental change is poorly constrained. A total of 23 proposal ideas were discussed, with ~12 of these deemed mature enough for active proposal development or awaiting scheduled site survey cruises. Of the remaining 11 proposals, key regions were identified where fundamental hypotheses are testable by drilling, but either site surveys are required or hypotheses need further development. Refinements are anticipated based upon regional IODP drilling in 2017/2018, analysis of recently collected site survey data, and the development of site survey proposals. We hope and expect that this workshop will lead to a new phase of scientific ocean drilling in the Australasian region in the early 2020s.The organizers gratefully acknowledge generous and critically important funding for participants’ travel to the workshop. Funding came from the Australian and New Zealand IODP Consortium (ANZIC), the US Science Support Program (USSSP), the Magellan-Plus Workshop Program of the European Consortium for Ocean Research Drilling (ECORD), the Japan Drilling Earth Consortium (J-DESC), the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), IODP-India, and the home institutions of numerous scientists

Mapping solar system chaos with the Geological Orrery

The Geological Orrery is a network of geological records of orbitally paced climate designed to address the inherent limitations of solutions for planetary orbits beyond 60 million years ago due to the chaotic nature of Solar System motion. We use results from two scientific coring experiments in Early Mesozoic continental strata: the Newark Basin Coring Project and the Colorado Plateau Coring Project. We precisely and accurately resolve the secular fundamental frequencies of precession of perihelion of the inner planets and Jupiter for the Late Triassic and Early Jurassic epochs (223–199 million years ago) using the lacustrine record of orbital pacing tuned only to one frequency (1/405,000 years) as a geological interferometer. Ex- cepting Jupiter’s, these frequencies differ significantly from present values as determined using three independent techniques yielding practically the same results. Estimates for the precession of perihe- lion of the inner planets are robust, reflecting a zircon U–Pb-based age model and internal checks based on the overdetermined origins of the geologically measured frequencies. Furthermore, although not indicative of a correct solution, one numerical solution closely matches the Geological Orrery, with a very low probability of being due to chance. To determine the secular fundamental frequencies of the precession of the nodes of the planets and the important secular resonances with the precession of perihelion, a contemporaneous high-latitude geological archive recording obliquity pacing of climate is needed. These results form a proof of concept of the Geological Orrery and lay out an empirical framework to map the chaotic evo- lution of the Solar System